The Post Crop Vignetting has been changed to give it a more natural look. The previous versions of vignetting in ACR looked painted on with no real control over how the effect was applied. In ACR 6, you can still apply a vignette this way, but using the Highlight Priority or Color Priority will give you a dodge or burn look similar to a traditional darkroom vignette.

Noise Reduction

Noise reduction, particularly luminance noise reduction, has been a problem with digital files. Too much reduction often softens the details beyond an acceptable level. The new ACR noise tools do a much better job here, making high ISO images more than usable. If you do find edges losing a bit of contrast after your adjustments, the Detail sliders can recover this nicely (Figure 10).

Figure 10

Puppet Tool

Puppet tool is like a warp tool for photographers, letting you modify elements in your image in a natural looking way (of course, you can always go extreme for unusual looks) that is likely to have people discussing the “is it real or edited” question all over again. Puppet Warp works by placing pins on your image and dragging them to a new position. In the images shown in Figures 11a and 11b, I've bent the trunk of the elephant to a new angle (image courtesy of Adobe).

Figure 11a

Figure 11b

Improved Painting

Photoshop adds a Mixer Brush to create painterly effects on your images. Similar to Corel Painter, you can now use bristle tips and color blending on a photograph to turn your images into a painting. When combined with a tablet like the Wacom Intuos 4, the level of control is excellent. Since this feature has been added, I haven't used Painter at all (granted, I'm not a power user of Painter by any means, but being able to stay in Photoshop, with a UI I'm familiar with, is worth it's weight in gold to me).

Figure 12a

Figure 12b

Workflow Improvements

I don't typically use Adobe Bridge, preferring Lightroom for my organization and much of my raw conversion work. Having said that, I'm pretty impressed with the newest version of Bridge. In particular, the new Mini Bridge, available as a panel from within Photoshop is a great timesaver (Figure 13). You have full navigation control, and the ability to select multiple files in the “Content Pod”, then applying commands like Image Processor, HDR Pro, and PhotoMerge.

Figure 13

Bridge now has a high quality web gallery feature with templates and customization options (Figure 14). You can also output direction to PDF with various templates and options like password protection, automatic playback, watermarking and more.
Many of the tools have been updated to streamline your workflow as well. As an example, the ruler tool now has a straighten option that will rotate and crop the photo automatically, and the crop tool has a Rule of Thirds overlay that makes it easy to position your crop into a preferred location (Figure 15).

Figure 14

Figure 15

Conclusion

I've only touched on the major enhancements in Photoshop CS5, particularly those that will appeal to photographers. There are plenty of other enhancements, including the 3D tools, Repousse - a new tool to create 3D extrusions, and gray scale tinting options via Actions that walks you through the process of creating a toned image.

It's not all without some controversy though. In particular, printing has been a hot topic with color management the main issue. In previous releases of Photoshop you could turn color management completely off, applying no profile to your image - needed for creating print profile charts. CS5 removes the No Color Management option from the Mac to avoid issues with the way Mac OS handles color management. Adobe is promising a separate application designed for printing charts with no color management. The other issue is that clicking Print now sends your file directly to the printer with no Page Setup in-between. You now need to select the Print Settings option to configure your printer. You still have all the options you did before, but it's a change in the workflow that will throw some people off at first.

If CS4 is working for you, I'd suggest downloading the trial version to see if the improvements are worth upgrading. For ACR users, it's a no-brainer. The improvements in this tool alone are worth the cost in my mind. 64-bit support on the Mac is going to be a big win with access to more memory and faster processing, but until your third party add-ons are updated, this will be limited for many people.

Compared to CS4, Photoshop CS5 is a more ambitious upgrade with lots of new features to explore and master. With that comes complexity, but Adobe has made good progress in making Photoshop more approachable for most.